This application relates to a scroll compressor having a check valve that is quicker to react than the prior art valves.
Scroll compressors are utilized in many modem refrigerant compression applications. In a scroll compressor, a pair of scroll members each include a base and a generally spiral wrap extending from the base. One of the two scrolls is caused to orbit relative to the other. The non-orbiting scroll typically has a central discharge port. Refrigerant is entrapped between the wraps, and as the wraps orbit relative to each other compression chambers which trap the refrigerant are reduced in volume. The refrigerant is thus compressed until it reaches the discharge port. At that point, the refrigerant can pass through the discharge port to an outlet port.
A check valve is often positioned near the discharge port. The purpose of the check valve is to reduce the occurrence of reverse rotation. Upon shutdown of the scroll compressor, the orbiting scroll is no longer driven to orbit relative to the non-orbiting scroll. Further, a quantity of refrigerant remains compressed and in a discharge chamber adjacent to port. Without a check valve, this quantity of refrigerant can move back into the compression chambers and drive the orbiting scroll in a reverse direction. This is undesirable.
Scroll compressors have been designed to have a check valve which is intended to close the discharge port and prevent this back flow as soon as possible after shutdown. Thus, the scroll compressors having discharge check valves with passages to communicate a returning fluid to a rear face of the valve are known such that the valve can be driven towards its closed position as quickly as possible. However, it would still be desirable to increase the efficiency and speed with which this check valve moves to the closed position.
In the disclosed embodiment of this invention, a retainer or stop for the check valve defines an open position. The stop is configured such that a surface, which provides the stop surface for the check valve has reduced surface area. Further, at the same time, the quantity of refrigerant which xe2x80x9cseesxe2x80x9d the back of the check valve is not increased in volume. This decrease in surface area reduces the stiction or holding force on the check valve. Thus, when the compressor stops, the quantity of refrigerant in the pocket volume drives the check valve to its closed position more quickly.
In further features of this invention, the stiction surface is reduced by a generally cylindrically relief extending around the retainer body. Preferably, this relief does not extend radially outwardly as far as the size of the check valve.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.